Dietary resistant starch protects against post-antibiotic intestinal damage by restoring microbial homeostasis and preserving intestinal barrier function in meat duck

Resistant starch (RS) is recognized as a nutritional strategy that supports gut and overall host health by modulating gut microbiota. To directly assess the effects of RS on gut microbiota and its role in improving intestinal barrier function in meat ducks, this study first established an antibiotic-induced microbial dysbiosis model, which was characterized by reduced gut microbial diversity, intestinal dysfunction, and an inflammatory outburst following antibiotic exposure. Whereafter, in addition to the control group, ducks treated with antibiotics for 7 consecutive days were further allocated to two groups and fed the basal diet and RS diet that derived from 12 % raw potato starch until 21 d. The results demonstrated that dietary RS supplementation reversed the antibiotic-induced reduction in microbial diversity and restored the Firmicutes-to-Bacteroidetes ratio. Additionally, RS inclusion enriched beneficial bacterial genera, including Coprobacter, Odoribacter, and Faecalibacterium (LDA score > 3). Post-antibiotic intervention led to a reduction in villus density and muscular thickness, accompanied by a significant downregulation (P < 0.05) of zonula occludens-1 and mucin-2 expression, along with increased serum pro-inflammatory cytokine levels (P < 0.05). Notably, dietary RS supplementation significantly enhanced (P < 0.05) the expression of glucagon-like peptide receptor and the anti-apoptotic factor Bcl-2, while suppressing caspase transcription. This resulted in increased villus height and muscular thickness in the ileum (P < 0.05). Furthermore, RS intervention remarkably reduced (P < 0.05) pro-inflammatory cytokine levels, particularly interleukin-1β and tumor necrosis factor-α, in both the ileum and serum. These effects were likely linked to alterations in cecal microbiota, including increased abundances of Barnesiella, Ruminiclostridium 9, Megamonas, Faecalitalea, Adlercreutzia, Coprobacter and Collinsella. In conclusion, dietary RS supplementation mitigated antibiotic-induced cecal microbial dysbiosis and restored intestinal structure by promoting enterocyte proliferation and reducing apoptosis. Consequently, RS supplementation helped alleviate systemic inflammation in meat ducks following antibiotic treatment.